Hearing testing of newborns and infants using auditory brainstem responses (ABR) has gained widespread acceptance and has come to be preferred over other less accurate techniques. ABR's strength is is direct measurement of auditory function which results in high test specificity and sensitivity. Clinical use of ABF, however, is still limited because of the professional labor intensive operation of existing devices. The need for extensive professional intervention during and after testing has led to limited use and consequently low production and high unit cost of ABR devices. One method of overcoming the practical drawbacks of ABR hearing testing is to develop automated devices which require minimal human intervention during a short testing period. The overall aim of the proposed work in phase I is to develop methods for automatic testing and analysis of auditory brainstem responses. Such methods would operate in real-time to achieve a desired measurement goal and obviate the need for human intervention for (1) discarding responses of undesired origin, (2)\recognizing the relevant waveforms, (3) and analyzing the overall results to provide efficient and accurate hearing thresholds. Therefore, during Phase I, APR responses will be collected from both infants and adults and used to evaluate efficient and sensitive techniques for signal analysis and thereshold detection. These techniques will then be used for the design of a cost-efficient automated microcomputer-based device.